Electrode for secondary battery

Abstract

An electrode for a secondary battery includes a current collector, a first electrode mixture layer disposed on at least one surface of the current collector and including styrene butadiene rubber, and a second electrode mixture layer disposed on the first electrode mixture layer and including a second styrene butadiene rubber. The first styrene butadiene rubber and the second styrene butadiene rubber have a repeating unit of styrene derived structure and a repeating unit of a butadiene derived structure, the first styrene butadiene rubber containing 40 to 90 mol % of a butadiene monomer based on total content of a monomer, and the second styrene butadiene rubber having a lower content of a butadiene monomer than the content of the first styrene butadiene rubber.

What is claimed is: 
     
       1. An electrode for a secondary battery, comprising:
 a current collector; 
 a first electrode mixture layer disposed on at least one surface of the current collector and including a first styrene-butadiene rubber; and 
 a second electrode mixture layer disposed on the first electrode mixture layer and including a second styrene-butadiene rubber, 
 wherein the first styrene-butadiene rubber and the second styrene-butadiene rubber include a repeating unit of a styrene-derived structure and a repeating unit of a butadiene-derived structure, 
 the first styrene-butadiene rubber contains 40 to 90 mol % of a butadiene monomer based on a total content of a monomer, and 
 the second styrene-butadiene rubber has a lower content of a butadiene monomer than the content of the first styrene-butadiene rubber. 
 
     
     
       2. The electrode for a secondary battery of  claim 1 , wherein the second styrene-butadiene rubber contains 5 to 35 mol % of the butadiene monomer based on the total amount of the monomer. 
     
     
       3. The electrode for a secondary battery of  claim 1 , wherein the content of the second styrene-butadiene rubber included in the second electrode mixture layer is the same as or lower than a content of the first styrene-butadiene rubber included in the first electrode mixture layer. 
     
     
       4. The electrode for a secondary battery of  claim 1 , wherein the first electrode mixture layer comprises 2.0 to 5.0% by weight of the first styrene-butadiene rubber, based on a total weight of the first electrode mixture layer. 
     
     
       5. The electrode for a secondary battery of  claim 1 , wherein the second electrode mixture layer contains 2.0% by weight or less of the second styrene-butadiene rubber, based on a total weight of the second electrode mixture layer. 
     
     
       6. The electrode for a secondary battery of  claim 1 , wherein the first electrode mixture layer comprises 2.0 to 3.5% by weight of the first styrene-butadiene rubber, based on a total weight of the first electrode mixture layer, and the second electrode mixture layer comprises 1.5% by weight or less of the second styrene-butadiene rubber, based on a total weight of the second electrode mixture layer. 
     
     
       7. The electrode for a secondary battery of  claim 1 , wherein at least one of the first and second styrene-butadiene rubbers includes at least one of a monomer having a structure derived from acrylate and a monomer having a structure derived from acrylonitrile. 
     
     
       8. The electrode for a secondary battery of  claim 1 , wherein the thickness of the first electrode mixture layer is in the range of 10 to 40 μm. 
     
     
       9. The electrode for a secondary battery of  claim 1 , wherein the thickness of the second electrode mixture layer is in the range of 10 to 100μm, and
 the first electrode mixture layer and the second electrode mixture layer have a thickness ratio of 1:1 to 1:3. 
 
     
     
       10. The electrode for a secondary battery of  claim 1 , wherein the electrode has an adhesive force of 0.15 to 0.38N/18 mm, between the current collector and a first electrode active material layer. 
     
     
       11. The electrode for a secondary battery of  claim 1 , wherein the electrode is a negative electrode. 
     
     
       12. A secondary battery comprising the electrode of  claim 1 . 
     
     
       13. The secondary battery of  claim 12 , wherein the electrode is a negative electrode.